Jones et al. – Penetrating abdominal trauma (version 20170821-2)

Penetrating Abdominal Trauma: Evaluation & Treatment

Charles Krin &Karim Brohi, London, UK, August 09, 2004; edited & updated by Christian Jones, Baltimore, MD, US, August 21, 2017

About this edition

The original version of this article on the evaluation of penetrating abdominal trauma was originally published on Trauma.org in 2004 with a large number of references and images. In an attempt to decrease the size of the article and update basic information, it has been heavily edited (for instance, all those references and images have been removed, a section on management of specific injuries has been added, and some anglicisms have been altered). This article has beenredesigned for informal or semi-formal teaching and has been updated without regard for citation or the pesky notion of rigorous evidence.Those desiring more formality (and content) are encouraged to read the original article or, even better, pretty much all of Top Knife by Hirshberg & Mattox. This article is distributed with the CC BY-NC-SA 2.5 license as found at the end of the article, and is not endorsed by nor a product of Trauma.org. The original may be found at This is version 20170821-2. The latest version can always be found at

Penetrating abdominal injury

The abdomen extends from the nipples to the groin crease anteriorly, and the tips of the scapulae to the gluteal skin crease inferiorly. Any penetrating injury to this area, or that may have traversed this volume, should be considered as a potential abdominal injury, and evaluated as such.

The incidence of penetrating injury will vary from hospital to hospital and region to region. Some institutions will have a very low incidence of penetrating trauma, and yet it is vital that penetrating injury is treated differently from blunt trauma. The mechanisms and physical characteristics of injury are different, as are the relevance and accuracy of investigations and the methods and timing of repair.

Presentation

Patients with significant penetrating abdominal injury tend to fall into 3 major categories:

Presentation / Likely injury / Managementpriority
Pulseless / Major vascular injury / Emergencylaparotomy or resuscitative thoracotomy with aortic cross-clamp
Hemodynamicallyunstable / Vascular and/or solid organ injury
AND/OR
Hemorrhage fromother sites / Identify & controlhemorrhage; damage control
Hemodynamically normal / Hollow viscus injury, pancreas, or renal / Identify presence of gastrointestinal, diaphragmatic, or retroperitonealinjury

The appropriate investigations and management pathway vary with each of these clinical presentations.

Pulseless

Patients who arrive without palpable pulses but with witnessed recent or current signs of life (e.g., pulseless electrical activity) need immediate laparotomy in the operating room for hemorrhage control. However, the ability to transfer such a patient from the ambulance bay directly to the operating room and start the laparotomy within 5 minutes of arrival is vital if this is to have any chance of success, and this is not possible in most centers.

A second option is to perform athoracotomy in the emergency departmentand cross-clamp the aorta. This is a poor second choice option as it does not completely arrest hemorrhage, delays laparotomy, and opens a second body cavity which will contribute to further heat and blood loss. This maneuver has a very low functional survivor yield, and yet remains the only hope for salvage in this group of patients where immediate access to an operating room is not available.

Hemodynamically unstable

There should be no delay in trying to resuscitate the patient prior to surgery.

Patients with penetrating trauma who are hemodynamically unstable require immediate operation. 'Haemodynamically unstable' includes non-responders and transient-responders to initial small-volume fluid bolus administration or transfusion. Patients should be taken immediately to the operating room, without further unnecessary investigations or interventions.

The only decision to be made in these patients is where is the bleeding and this which cavity to expose first. Where there is a stab or gunshot wound obviously involving the abdomen, the decision is simple, and the patient has a laparotomy.If there is a question about the abdomen being the source of the bleeding, FAST scan is used to determine the presence of free intra-peritoneal fluid. In the absence of ultrasound, diagnostic peritoneal aspiration is reasonable; aspiration of frank blood or succus confirms intraabdominal injury, and time for a formal lavage is unnecessary.

The decision to perform a laparotomy may be complicated if:

  • There are multiple stab wounds/gunshot wounds to multiple cavities.
  • The wounds are at, or cross, junctional zones (e.g., the costal margin, groin, or buttocks).
  • There is evidence or the possibility of cardiac tamponade

The diagnosis ofmassive hemothoraxmay be made clinically, with aFASTscan,chest tubeor Chest X-ray, depending on the degree of shock present and the rapidity with which such tests can be performed. Cardiac tamponade may be diagnosed withFASTor in the operating room with a pericardial window.

It is more important to take the patient to the operating room and commence surgery than to make a definitive diagnosis. If a thoracic injury is suspected during a laparotomy a hemithorax can be explored through the diaphragm or a formal thoracotomy, and a tamponade explored through a pericardial window and sternotomy.

Hemodynamically Normal

Patients with clinical signs of peritonitis or with evisceration of bowel should be taken immediately to the operating room.

Currently there are several possible options for the evaluation of penetrating abdominal trauma in the hemodynamically normal trauma patient without signs of peritonitis. Many of these patients will have some superficial tenderness around the wound site, but no signs of peritoneal inflammation.

The goal of any algorithm for penetrating abdominal trauma should be to identify injuries requiring surgical repair, and avoid unnecessary laparotomy with its associated morbidity.

Adjuncts to the initial evaluation of the trauma patient can provide clues to significant intra-peritoneal injury:

  • Chest X-ray
    An erect chest radiograph may identify sub-diaphragmatic air. This must be interpreted with some caution in the absence of peritonitis, as air may be entrained into the peritoneal cavity with a stab or gunshot wound. However it certainly signals peritoneal penetration and warrants further investigation.
  • Nasogastric Tube
    Blood drained from the stomach will identify gastric injury.
  • Urinary catheter
    Macroscopic hematuria indicates a renal or bladder injury. Microscopic injury suggests but is not pathognomonic of ureteric injury.
  • Rectal examination
    Rectal blood indicates a rectal or sigmoid penetration. Proctoscopy & sigmoidoscopy should be performed (see below)

Options for evaluation

Further evaluation requires the use of one or more of the following diagnostic modalities:

  • Serial Physical Examination (PE)
  • Local Wound Exploration (LWE)
  • Diagnostic Peritoneal Lavage (DPL)
  • Ultrasound (FAST)
  • CT Scan
  • Laparoscopy
  • Laparotomy

These different methods, each discussed below, are by no means equal. The decision on which method, or combination of methods, to choose will depend primarily on hospital factors such as trauma patient load, access to inpatient beds, availability of in-house surgical teams, access to high resolution CT scanners, etc. Whichever decision tree is chosen should be accepted at a hospital-wide level. The practice should not change from surgeon to surgeon and day to day. The algorithm should be routinely audited for missed injuries, effectiveness, and use of resources.

Serial physical examination

Serial physical examination has the best sensitivity and negative predictive value of all modalities for the evaluation of penetrating abdominal trauma.

The patient is admitted for observation for 24 hours. During this time the patient is has frequent (hourly), regular checks of their hemodynamic status. The abdomen is examined routinely for signs of developing peritonitis. Ideally the same surgeon should examine the patient each time. If this is not possible, during a handover period both surgeons should examine the patient at the same time so they agree on the current status of the abdomen and whether there has been any progression in symptoms. The timing of examinations varies inthe literature, but should probably start out more frequently and then decrease over time. A suggested sequence of examination might be at 1, 4, 12 and 24 hours after the initial assessment. Some authors recommend examination every four hours.

If the patient develops signs of hemodynamic instability or peritonitis during this period of observation, a laparotomy is performed. If the patient is well the following day they start a normal diet, and are discharged once diet is tolerated and they have completed the observation period.

Patients who do not develop frank peritonitis, but who have persistent local symptoms of pain and tenderness, with perhaps a fever or tachycardia at 24 hours should be evaluated by another modality: CT scan, laparoscopy, or laparotomy.

The disadvantages of serial physical exam are primarily the requirement to admit all patients with a penetrating injury, and the requirement for frequent hemodynamic and physical examinations. This usually requires the patient to be in a high dependency type setting, and requires a body of in-house surgeons to perform the serial evaluations.

Local wound exploration

Local wound exploration (LWE) requires a formal evaluation of a stab wound under at least local anesthesia. This procedure is usually performed in the operating room, but is performed in the emergency department by some institutions. This procedure is not a simple probing of the wound with a cotton swab, and is not the basic retraction of edges in an attempt to visualize the wound base. The wound must be extended enough to allow following the track through tissue layers; this is often extension of the wound and exposure of the fascia for several centimeters.

Penetration of the anterior fascia is considered a positive LWE, as penetration of the peritoneum is difficult to identify. A positive LWE leads to either laparotomy or diagnostic laparoscopy.

When LWE is used alone to determine laparotomy, there will be a high non-therapeutic laparotomy rate. Even if peritoneal(rather than anterior fascial) penetration were used as a cut-off, many of these patients will have no intra-peritoneal injury, or an injury that does not require surgical intervention—most commonly omental laceration, mesenteric laceration, or liver tears that have stopped bleeding.

Diagnostic peritoneal lavage

Diagnostic peritoneal lavage (DPL), though seldom practiced in the era of bedside ultrasound, may remain a useful adjunct with FAST is unavailable. This involves passing a small catheter into the peritoneal cavity, usually at the umbilicus or just inferior to it. If blood can be aspirated through this catheter, this is referred to as a positive 'tap' or aspiration (DPA). If no blood can be aspirated a liter of warm crystalloid solution is run into the peritoneal cavity and then allowed to drain out. This lavage fluid is traditionally then sent to the laboratory for analysis of red cell count, white cell count, and any bowel contents (feces, succus, or food matter).

It is important to realize that the role of DPL in the hemodynamically stable patient is different from that in the unstable patient. In the unstable patient the problem is one of major hemorrhage. DPL is used as an alternative to theFAST scanto identify intraperitoneal hemorrhage only when the cavity of penetrating injury is unknown. In the unstable patient one is searching for a lot of blood, so a positive DPL in this setting requires either a positive aspiration.

A hemodynamically unstable patient with aclearly abdominal stab wound needs no further investigations and will proceed to laparotomy, as discussed above. So the role of DPL in the hemodynamically normal patient with penetrating abdominal injury is to identify hollow viscus injury (stomach, small bowel, or colon) or diaphragmatic injury, either of which is more easily and safely performed with alternative tools.

FAST

The role of FAST in penetrating trauma has not been as fully evaluated as in blunt injury. FAST is sensitive for pericardial fluid and can be used, like DPL, to evaluate whether the abdomen is the source of massive bleeding in the hemodynamically unstable patient. Ultrasound as yet cannot detect the small amounts of fluid which may be associated with a hollow viscus injury, so for the hemodynamically stable patient:

  • A positive FAST indicates peritoneal penetration and mandates at least diagnostic laparoscopy, but is poor at discriminating for injuries requiring intervention
  • A negative FAST does not exclude significant abdominal injury

CT

CT scanning is finding an increasing role in the evaluation of penetrating abdominal injury. A modern scanner with triple-contrast protocol (intravenous, oral and rectal) is sensitive for most major abdominal injuries, and identifies secondary signs of injury for those not visualizable. With ability to recognize those secondary signs, the oral and rectal contrast are probably also unnecessary. Of all the diagnostic modalities listed, CT gives the best assessment of retroperitoneal structures.

The CT, however, is most useful for defining the tract of extraperitoneal penetrating wounds and allowing disposition of patients without further evaluation. If an obvious tract is present and does not violate the abdominal fascia, the wound can be cleaned and closed and the patient discharged. However, lack of a visualized tract does not imply this; further evaluations (typically wound exploration or diagnostic laparoscopy) are needed. Positive CT signs mandating at least laparoscopy include:

  • Free intraperitoneal air
  • Free intraperitoneal fluid
  • Wound track extending through fascia or through retroperitoneum to colon
  • Bowel wall thickening
  • Intraperitoneal fat stranding
  • Intraluminal contrast leak
  • Intravenous contrast extravasation
  • Diaphragmatic defect (for which the CT still has low sensitivity)

The use of CT for penetrating intraabdominal injury is again unnecessary and even contraindicated for the hemodynamically unstable patient, or for the hemodynamically stable patient with a positive FAST or obviously penetrated peritoneum (such as with eviscerated bowel). These patients should go directly to the OR.

Laparoscopy

A full trauma laparoscopy for the evaluation of penetrating injury still requires general anesthesia and complete examination of intra-peritoneal contents, including visualization of the whole small bowel and intra-peritoneal colon. In most studies laparoscopy has a significant false negative rate, primarily from missed bowel injuries. Laparoscopy is also limited in the evaluation of retroperitoneal injury. While an expert laparoscopist can capably run the bowel, the other limitations require any finding of peritoneal violation—certainly any finding of significant hemoperitoneum—to nearly mandate laparotomy. The best exception to this laparoscopy undertaken in the setting of a thoracoabdominal wound requiring evaluation for diaphragmatic injury. A laceration of the right diaphragm and no other blood in the abdomen can typically be repaired laparoscopically without the need to open. While a left diaphragm laceration is more likely to be associated with intraperitoneal injury, most authors suggest handling these similarly. In either case, of course, care must be taken to avoid higher insufflation pressure which would result in a hemodynamically significant pneumothorax.

Laparotomy

Exploratory laparotomy for all penetrating abdominal wounds still has a role in resource-limited environments, or occasionally in cases of multi-cavitary injuries. For most situations however the non-therapeutic laparotomy rate will be unacceptable high. With the incidence of complications with a negative laparotomy at of 12%-41%, it is difficult to support such a strategy where adjunctive methods such as CT or FASTare available and serial physical examination has such a low missed injury rate.

Special Situations

Wounds to thoracoabdominal junction zone

Thoracoabdominal injuries need to be evaluated for diaphragmatic injury. Where there is evidence of thoracic and abdominal injury there must, by definition, be an injury to the diaphragm. For example, if there is a right pneumothorax and a liver laceration, the diaphragm must also be torn.
If the evidence for this is less clear, but diaphragm injury is still suspected, the options are ultrasound, MRI, CT or laparoscopy/thoracoscopy. All radiological studies may miss small diaphragmatic tears, and so laparoscopy/thoracoscopy remains the investigation of choice. Laparoscopy is preferred for left sided injuries, thoracoscopy or laparoscopy for right sided injuries. Diaphragmatic lacerations may also be repaired through a laparoscopic or laparoscope-assisted approach.

Flank or back wound

Flank or back wounds may be associated with injuries to retroperitoneal organs such as the colon, kidney and lumbar vessels; or more rarely the pancreas, aorta and inferior vena cava. Of these, the colon is the injury most often missed. Where colon injury is a possibility, the duration of serial physical examination is extended to 72 ours, watching for fever or a rise in the white cell count. An alternative is to perform a triple-contrast CT scan. When the wound track extends up to the colon, or there is evidence of abnormal bowel wall thickening, laparotomy is indicated.

Wound to buttock or perineum

The most dangerous missed injury here is the occult rectal injury. Any penetrating injury to the gluteal region carries the risk of rectal injury. Digital rectal examination is inadequate and full proctoscopy and sigmoidoscopy should be performed, looking for the presence of blood and/or a mucosal tear.

Recommended approaches

Which diagnostic tree a hospital chooses for the evaluation of penetrating injury will be dependent on numerous factors, including trauma patient load, surgical team availability and coverage, the availability of CT scanners and trauma radiologists, and access to the operating room and critical care beds.

Many different systems are used around the world. The following recommendations form a reasonable simple algorithm for modern trauma centers, but are by no means the only possibilities. Each diagnostic tool is associated with the caveats listed above.

  1. ABCs
  2. If the patient is hemodynamically unstable and has multiple potentially injured body cavities, perform FAST to distinguish between them.
  3. If the patient is hemodynamically unstable with an abdominal injury (either identified by FAST showing intraabdominal fluid or obvious abdominal wound location), or is hemodynamically stable and has peritonitis, evisceration of omentum or bowel, leakage of succus or stool, oruncontrolled bleeding, proceed to OR for laparotomy.
  4. If the patient is hemodynamically stable and has none of the above, perform FAST; if intraabdominal fluid is identified, proceed to OR for laparotomy.
  5. If stable and none of the above, obtain high-resolution CT with IV contrast. Any of the findings listed above in the “CT” section should result in laparotomy.
  6. If there are none of the above, and CT demonstrates only an obvious tract outside the abdominal fascia (not the absence of a tract that penetrates, but a clear one that does not), the patient may be discharged after appropriate local wound care.
  7. If there are none of the above, consider serial abdominal exams for 24 hours, diagnostic laparoscopy, or local wound exploration. Choice of these is dependent upon surgeon preference and available resources.

Management of select injuries